A simple but brilliant game, Space Taxi put you in control of an intergalactic flying-taxi driver and tasked you with ferrying passengers to and from locations while battling each level’s gravitational force. The acceleration of the rocket-powered cab was influenced by the spaceship movement in Atari’s Asteroids, but the main idea for Space Taxi, like Kutcher’s passion for programming as a whole, came from his aptitude for maths. “In high school I did a science fair project where I programmed some gravity equations in that,” he explains. “It was pretty easy because [the game] loops continuously, and in each loop it just moves everything so it keeps track of the acceleration, vertical and horizontal, and in each loop it just says: ‘speed = (speed + acceleration)’, which could be positive or negative depending on whether you’re accelerating or decelerating.” He’s lost us, but we trust that the program’s as easy as he says. “Then, for the gravity, based on which direction I wanted it to pull, I just had a constant acceleration force in that equation,” he continues. “So it’s actually very easy because when you break it down into the game loop it’s kind of like taking it down into the first derivative of calculus where you really just need to keep adding your acceleration to get your velocity and keep adding your velocity to get to your position. And then I varied the gravity in different directions with different strengths each level just by changing two or three numbers.” Simple…
With the basic handling in place, Kutcher could concentrate on the presentation – specifically the visual design of each stage – which, surprisingly, proved trickier than the physics. “On the C64 I had to use the custom character set for most of the graphics. That’s probably the one limitation I worked around, that all the backgrounds had to be done that way, so I had to get clever to make up character sets that I could re-use to make different scenes. If you look at the levels, you’ll notice that similar blocks were used to make all different types of objects. I only ever used true bitmap graphics for the things that actually moved, like the taxi, the man, the big snowflakes.”
And on the subject of presentation, there’s no ignoring Space Taxi’s most memorable feature:
its speech. In what seemed like one of the most hi-tech examples of game sound at the time,
Space Taxi actually talked. Start a level and the stickman passenger would wave at you and audibly cry out ‘Hey, taxi!’ to get your attention. In 1984, simple words marked Space Taxi out as a remarkable achievement and lent the game a unique charm and personality that ensured people would remember it fondly for the next 25 years.
“It seems common today. Voice recording is nothing impressive here in the present,” notes Kutcher as he, rather fittingly, responds to our questions via his own MP3 recording. “But back in 1983 there wasn’t an easy way to do that.” A passionate engineer, as well as programmer, Kutcher built his own voice sampler from off the-shelf components. “I remember buying all these analogue-to-digital converters and built my own little circuit that could take your voice and sample the voltage very rapidly then convert it to a digital value,” he reveals. “I then interfaced it into the TRS80 and eventually the C64. I basically built my own electronics that would take samples and then record the binary data, which I then played back sending a voltage to the speaker based on the voltage settings I recorded. If you varied the speed of playback, you could change the pitch or make the voice faster or slower. The C64 had a few extra built-in pieces so I didn’t need my own hardware to play back the speech like I did with the TRS80. But I did use the contraption to record my own voice for Space Taxi.”
Developed during a five-week college break, Space Taxi was completed in the autumn of 1983, and after receiving a soundtrack from Castle Wolfenstein creator Silas Warner, it was released to the world to huge critical acclaim in 1984. “I’m particularly proud of the magazine reviews it received,” says Kutcher. “Every month, the marketing guy at Muse did a great job of getting press coverage and it received reviews in all the mags. It was nominated for a Game of the Year award by Electronic Games magazine and it received a Consumer Electronics Showcase award. I was honored but I had no idea at the time how big CES was. It’s a massive show and to be one of the ten showcased games that year was a great honor.
If there’s one thing Kutcher wishes he could have done better it’s the marketing. “Space Taxi had the potential to be a much bigger hit. Some other games at the time sold up to 40 times more and I didn’t believe they were much better. I think the timing was bad at Muse. Space Taxi was selling like crazy, but once Castle Wolfenstein came out, efforts were redirected and Space Taxi languished after that.”
Though not a huge hit, Space Taxi sold around ten thousand copies in its first year, and with Kutcher netting a ten per cent royalty on the sale, he eventually earned around ten thousand dollars. “Enough to pay for a big chunk of my college fees.” After Space Taxi, he worked part-time for Muse until it closed down and most of the staff moved to Microprose. “I did some programming for them and converted Sid Meier’s Solo Flight: 2nd Edition to C64.”
“Ultimately, I continued working for Dr Sacco who was in the field of medical software. I became a partner before leaving to grow my own company. I’ve been focusing on medical database software for several years now and have drifted away from games. The thing I always enjoyed was programming so it didn’t really matter whether I was doing a game or software, I guess it’s just the way things unfolded.”
Although Kutcher moved away from games, Space Taxi remains a very important project for him. “It has very fond memories for me. It was developed in a short period of time but it had a profound effect on my career. I guess you could say I got a college education out of Space Taxi.”